Synthesis of Nanowire and Hollow LiFePO4 Cathodes for High-Performance Lithium Batteries

Abstract

The synthesis of nanowire and hollow LiFePO 4 cathodes using the hard templates KIT-6 and SBA-15 is reported for high-performance lithium batteries. The two-dimensional hexagonal SBA-15 silica template with P 6 mm symmetry is used for the template that contains parallel cylindrical pores arranged with hexagonal symmetry, which serves to organize the wires into parallel bundles. On the other hand, three-dimensional cubic arrangement of pores in KIT-6 silica with Ia 3 d symmetry yields hollow morphology with mesopores. After impregnation of the template into a solution or after coating on the template with a solution consisting of LiFePO 4 precursors, the silica template is removed and is subsequently fired at 700 °C. Electrochemical cycling of both the nanowire and hollow LiFePO 4 cathodes demonstrates excellent rate capability even above 10C rate, showing >89% capacity retention of the initial capacity. Among them, the rate capability of the hollow cathode at 15C is higher than that of the nanowire cathode, showing 6% improvement due to its higher Brunauer−Emmett−Teller surface area.